The most recent development in starch production was determined by two essential findings which contributed considerably to economical production. The first finding was that starch kernels which are damaged during grinding decrease the subsequent yield of pure starch in the starch factory. If the starch is damaged in the production of dough products, for example, the contents of the damaged starch kernels, when cooked, occur as losses in the cooking water and also give the cooking water a milky-white color. But the same is also true in the production of starch. The starch can only be separated from the gluten in an economical manner in that the protein bodies, which are already thread-shaped in themselves, are arranged to form a protein framework (gluten framework). This occurs by way of the formation of dough in the same way as in dough products. The starch crystals can then float out of the protein framework by means of additional water and can be separated. In contrast, the baker wants the starch to be damaged in bread flour so that the flour can quickly absorb much water for the formation of the bread dough.
The second finding consisted in keeping the number of grinding passes used for milling as low as possible, which allowed the initial costs for the mill to be kept as low as possible. The solution corresponding to these two findings is described in the present Applicant's DE-PS No. 2 642 628. Ten to twelve grinding passes are used in this prior art.